CAN0 FD‘s BRS&ESI&DLC waveform is strange

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CAN0 FD‘s BRS&ESI&DLC waveform is strange

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chengsz1206
Contributor II

According to  CAN FD spec,the BRS+ESI+DLC is 6bit。

But their waveform is not 6bit。I find the waveform  is strange。

The wave form is as follow。Who can help me?

FD.PNG

For details,please refer to CAN FD _issue.xlsx。

1 Solution
661 Views
PetrS
NXP TechSupport
NXP TechSupport

Hi,

the waveform is correct.

The bit meaning of the CANH signal is below

CAN fd frame1.png

when zooming into bitrate switching...

CAN fd frame 2.png

At the sample point of BRS bit the bitrate is switched, so BRS bit is little bit shorter then previous bits.

Within DLC bits a stuff bit of opposite polarity is inserted after five bits of same polarity are detected.  

BR, Petr

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1 Reply
662 Views
PetrS
NXP TechSupport
NXP TechSupport

Hi,

the waveform is correct.

The bit meaning of the CANH signal is below

CAN fd frame1.png

when zooming into bitrate switching...

CAN fd frame 2.png

At the sample point of BRS bit the bitrate is switched, so BRS bit is little bit shorter then previous bits.

Within DLC bits a stuff bit of opposite polarity is inserted after five bits of same polarity are detected.  

BR, Petr